Nonionic Hydrocarbon Surfactants Research Articles

Influence of typical liquid fuels on foam properties of critical components of environmentally friendly aqueous film-forming foams

In this study, the influence mechanism of typical fuels (oils) on the foam properties of mixture of hydrocarbon and fluorocarbon surfactants was investigated. A mixed solution was prepared based on a nonionic hydrocarbon surfactant (APG-0810) and a zwitterionic C6 fluorocarbon surfactant (short-chain). The effect of different oils (heptane, kerosene, diesel, and transformer oil) on the physical property parameters, foamability, oil resistivity of foam and single vertical liquid film of the mixture are systematically investigated. Results indicate that the viscosity of mixture increases, but the conductivity, surface activity, and initial foam height decreases with addition of the four oils. The drainage and volume decay of the foam are accelerated by the presence of oils. In addition, the presence of oils accelerates liquid film thinning through affecting drainage, especially for the oil with higher density, water solubility, and volatility. The four oils showed different effect on foam properties due to the difference in nature and emulsification of them. Among them, the foam properties under the action of heptane is the best, and the oil resistivity of foams is the best. This study can provide theoretical guidance for oil resistivity of hydrocarbon and fluorocarbon surfactant stabilized foams.

QSPR-based prediction of air-water interfacial adsorption coefficients for nonionic PFAS with large headgroups

Air-water interfacial adsorption has been demonstrated to be an important process affecting the retention and distribution of PFAS in soil, surface waters, and the atmosphere, as well as being central to certain remediation methods. Measured or estimated air-water interfacial adsorption coefficients are needed for quantifying and modeling the interfacial adsorption of PFAS. A single-descriptor QSPR model developed in prior work for predicting air-water interfacial adsorption coefficients of PFAS was demonstrated to successfully represent more than 60 different PFAS, comprising all headgroup types and a wide variety of tail structures. However, the model overpredicted values for nonionic PFAS with very large headgroups. A revised QSPR model was developed in the present study to predict air-water interfacial adsorption coefficients for nonionic PFAS with large headgroups. A two-descriptor QSPR model employing molar volume and headgroup-to-tail molar-volume ratio successfully represented measured data for both nonionic PFAS and nonionic hydrocarbon surfactants. This new model provides a means to produce estimates of air-water interfacial adsorption coefficients for nonionic PFAS for which measured values are typically not available.

Effect of silicones and polymers on the wetting and foaming properties of anionic and nonionic hydrocarbon surfactants.

To better understand the effects of nonionic silicones and polymers on the wetting and foaming properties of anionic and nonionic hydrocarbon surfactants and different forces between molecules, nonionic silicone surfactant (GT-248), polymer (HPMC), anionic surfactant (AES), and nonionic surfactants (APG0810) were selected. The CMC ratio is used as a reference to determine the concentration ratio of the APG0810/GT-248 and AES/GT-248 compound solutions, after which HPMC was added to form a compound solution to test the wetting and foaming properties of the compound solution. The results showed that GT-248 obtained a high density of methyl groups on the surface of the solution due to its excellent spreadability and good flexibility of the siloxane chain, effectively reduces the surface tension and wetting time of AES and APG0810 solutions. But in terms of foam performance, after adding GT-248 to solution, the foam stability of AES solution is enhanced, the foam height of AES solution was reduced by 33.7%, the foam stability of APG0810 solution is weakened a lot, and the foam height of APG0810 solution was reduced by 85.4%. Mainly because of the difference in electronegativity between the AES and APG0810 head groups, the strong electronegativity between the AES head groups resulted in a smaller number of GT-248 insertions in the liquid film, which weakened the defoaming effect of GT-248. The weak interaction between the head groups of APG0810 resulted in a higher amount of GT-248 in the liquid film, and thus, the foam performance was greatly reduced. After the AES/GT-248 compound solution was preferred, by comparing the viscosity, surface tension, and the half-life of the foam, it was found that the addition of low concentration of polymer effectively improved the half-life of the foam without affecting the foaming properties, and the final choice of 4:1(AES/GT-248) + 1mgHPMC and 2:1(AES/GT-248) + 1mgHPMC composite solutions can be used as a superior dust suppression material.

Influence of nanoparticles on rheological properties and foam properties of mixed solutions of fluorocarbon and hydrocarbon surfactants

Mixed dispersions of silica nanoparticles (NPs), nonionic hydrocarbon surfactant (APG0810), and fluorocarbon surfactant (FS-50) in water were prepared. The molecular interactions, rheological properties, and foam properties of the mixed dispersions were experimentally investigated. The enhancement mechanism of the NPs on the foam stability of the mixture of APG0810/FS-50 was analyzed. Results showed that the NPs strongly influenced the rheological and foam properties of the mixed solutions. The viscosity of the APG0810/FS-50/NPs dispersions varied linearly with the shear rate, and the viscoelastic modulus of the dispersions increased with increasing NP concentration. With the increase of NP concentration, the foam stability was enhanced but the foaming properties was weakened. Foam drainage, foam coarsening, and foam mechanical strength were apparently enhanced because of the aggregation of a large amount of NPs in the plateau borders. This research gives theoretical guidance for the application of NPs in fire extinguishing agent.

Comparison of the properties of perfluoroalkyl polyoxyethylene ether and alkyl polyoxyethylene ether

Short-chain fluorocarbon surfactants have been widely adopted as substitutes for long-chain fluorocarbon surfactants and hydrocarbon surfactants due to their biodegradability and excellent surface properties. In particular, fluorocarbon surfactants such as short-chain perfluoropolyethers have become a research hotspot in recent years. In this study, the short-chain perfluoroalkyl polyoxyethylene ether surfactant CF-310 is systematically compared with the traditional nonionic hydrocarbon surfactant alkyl polyoxyethylene ether AEO-7 in terms of its equilibrium surface tension, dynamic surface tension, wetting properties, and foam properties. The results show that CF-310 has better surface properties, better wettability on low-energy surfaces, and better foam properties than AEO-7. Structural optimization based on density functional theory (DFT) also indicates that the CF-310 fluorocarbon chain has a larger volume and a helical conformation, which are the main factors responsible for the superior surface performance, wettability, and foam performance of CF-310 compared with AEO-7. Excellent performance and biodegradability make this short-chain perfluoroalkyl polyoxyethylene ether surfactant CF-310 a more efficient alternative to AEO-7. This study tested the performance of the CF-310 system in hopes of developing its potential applications in personal and home care and foam applications.

Experimental Evaluation of Protecting High-Voltage Electrical Transformers Using Water Mist with and without Additives

Suppression of high-voltage (HV) electrical fires is difficult because it requires fire-extinguishing agents with good isolation properties as well as high fire-suppression efficiency. In the work presented herein, water mist with and without various water mist additives (WMAs) was utilized to suppress HV transformer oil fires. The WMAs included ionic alkali-metal salt and fluorocarbon surfactant, and nonionic hydrocarbon and fluorocarbon surfactants. At the same concentration, the surfactants were more efficient at extinguishing fires compared with the alkali-metal salt. The fluorocarbon surfactant was more efficient at extinguishing fires than the hydrocarbon surfactant, achieving flame extinction in 18 % of the time required when using natural water (NW). Besides, the effects of WMAs on the insulating properties of the water mist were studied. The gap breakdown test showed that the NW mist could increase the breakdown voltage of air by up to 5 % at 70-cm gap distance. Comparatively, the nonionic WMAs did not affect the insulating property of the NW mist, with the mist containing 1.0 % ionic KHCO3 solution enabling a reduction of up to 16 % in the breakdown at 70-cm gap distance while increasing the leakage current of the simulated insulator by up to 250 % at its nominal voltage. Finally, field tests were performed where NW mists were discharged onto a charged 220-kV high-voltage transformer. This study proves that NW mist and mists with nonionic WMAs are suitable for protecting HV electrical equipment, having important implications for extending the applications of water mist.

Binding of Procaine Hydrochloride to Hydrocarbon and Fluorocarbon Surfactants: The Role of Hydrophobicity

Aims: The interaction of procaine hydrochloride (PC.HCl) with sodium dodecyl sulfate (anionic hydrocarbon surfactant; SDS), Tween 20 (nonionic hydrocarbon surfactant), cetyltrimethyl ammonium bromide (cationic hydrocarbon surfactant; CTAB), lauryl sulphate betaine (amphoteric hydrocarbon surfactant; LSB) and Zonyl-FSN100 (non-ionic fluorocarbon surfactant; Zonyl FSN) has been aimed to study by UV-vis spectrophotometry. Methodology: Interactions with a fixed concentration of PC.HCl in the wide concentration range of Tween 20, Zonyl FSN, SDS, CTAB and LSB were studied spectrophotometrically at 298 K. Binding constants of PC.HCl to micelles was determined by using the Benesi-Hildebrand Equation. Results: Comparison of the binding constants (KB) showed that the most binding tendency of PC.HCl to micelles in case of Zonyl FSN. Due to the electrostatic repulsion between cationic CTAB and cationic PC.HCl the binding constant could not be calculated. The effect of Zonyl FSN on the binding of PC.HCl to hydrocarbon micelles has been also studied in the presence of fixed micelle concentration of Zonyl FSN. The binding tendency has been found to be related to the hydrophobicity of the medium. Conclusion: Interactions between different surfactants and amphiphilic drug PC.HCl showed that binding tendency of PC.HCl followed the order as; Zonyl FSN > Tween 20 > SDS > CTAB > LSB and presence of Zonyl FSN micelles increased incorporation of PC.HCl to all types of micelles.

Critical Microemulsion Concentration and Molar Ratio of Water-to-Surfactant of Supercritical CO2 Microemulsions with Commercial Nonionic Surfactants: Experiment and Molecular Dynamics Simulation

The critical microemulsion concentration (cμc) and the molar ratio of water-to-surfactant (W0) of supercritical CO2 (scCO2) microemulsion that uses different nonionic hydrocarbon surfactants (LS-36, LS-45, LS-54, DYNOL-604, TMN-6) were examined at temperatures from 35 to 45 °C and pressures up to 19 MPa. The results show that the cμc mainly depends on the structure of the surfactant. The surfactant with more hydrophilic structure, such as the ethylene oxide (EO) group and hydroxyl, tends to produce a higher cμc. In addition, the cμc increases with the increase of the ratio of ethylene oxide (EO) group number to the propylene oxide (PO) group number of the surfactant. The capacity of the microemulsion system to dissolve water, which is characterized by W0, is related to the concentration and structure of surfactant. It is found that a higher solubility of surfactant in CO2 favors the system to dissolve water at lower pressure. At higher pressure, the stronger hydrophilicity of surfactant and the higher sur...

Experimental Study on Foam Properties of Mixed Systems of Silicone and Hydrocarbon Surfactants

AbstractSilicone surfactants are inevitably involved in industrial applications in combination with hydrocarbon surfactants, but properties of the mixtures of silicone and hydrocarbon surfactants have received little attention, especially foam properties of the mixtures. In this study, aqueous solutions of respective binary mixtures of a nonionic silicone surfactant with anionic, cationic, and nonionic hydrocarbon surfactants were prepared for evaluation of their foam properties. Surface tension of aqueous solutions of the mixtures were measured with the maximum bubble pressure method. Foaming ability and foam stability of the mixtures were then evaluated with the standard Ross–Miles method. The findings show that the addition of the silicone surfactant results in a decrease in surface tension for aqueous solutions of the hydrocarbon surfactants. The critical micelle concentration (CMC) of the hydrocarbon surfactants is also changed by the additive silicone surfactant. Additionally, clear foam synergistic effects were observed in the mixtures of silicone and hydrocarbon surfactants, regardless of the ionic types of the hydrocarbon surfactant. The foam stability of the hydrocarbon surfactant was shown to generally improve with the increasing concentration of the silicone surfactant. Even so, aqueous solutions of different ionic hydrocarbon surfactants in the presence of the silicone surfactant will give different foam stabilities. The results of the present study are meant to provide guidance for the practical application of foams generated by the mixtures of the silicone and hydrocarbon surfactants.

Solubility of Nonionic Hydrocarbon Surfactants with Different Hydrophobic Tails in Supercritical CO2

The experiment utilizes a high-pressure view chamber that mainly aims at identifying the effect of surfactant architecture on solubility in CO2. First, when solubility pressures of three series of nonionic hydrocarbon surfactants are measured, results reveal that surfactants with a methylated tail exhibit the best solubility. Unexpectedly, surfactants with a branched tail show worse solubility than linear surfactants. This is conjectured to be caused by attractive molecule–molecule interactions. TX45 that possesses the shortest ethylene oxide chain and a highly methylated tail performs the best in CO2 solubility. Additionally, the experimental study on the solubility of TX45 in CO2 at T = (318 to 343) K demonstrates that solubility has a direct correlation with pressure and CO2 density, while it is inversely related to temperature. Finally, when we look at effects of the added alcohols on surfactant TX45 solubility, the results indicate that hexanol is the most effective alcohol in enhancing solubility. T...

Activity coefficient at infinite dilution of aqueous solutions of nonionic hydrocarbon and fluorocarbon surfactants as well as their ternary mixtures

AbstractActivity coefficients at infinite dilution of the aqueous solutions of nonionic hydrocarbon surfactants, p-(1,1,3,3- tetramethylbutyl) phenoxypoly(ethylene glycols), Triton X-100 (TX100) and Triton X-165 (TX165), fluorocarbon surfactants, Zonyl FSN-100 (FSN100) and Zonyl FSO-100 (FSO100) and their ternary mixtures were determined from the Gracia-Fadrique et al. method for non-volatile compounds. The values of activity coefficients were calculated taking into account the surface tension data of the studied systems at 293K and compared to those determined on the basis of the values of the contact angle of solutions on the polytetrafluoroethylene (PTFE) and polymethyl methacrylate (PMMA) surfaces and the solid-liquid interface tension.

Aggregation Behavior of Brij-35/Perfluorononanoic Acid Mixtures

The mixed system of a nonionic hydrocarbon surfactant, polyoxyethylene (23) lauryl ether (Brij-35), and a perfluorinated surfactant, perfluorononanoic acid, was investigated by a combination of methods. The critical micelle concentrations (cmc's) have been determined over a wide range of sample compositions by fluorescence and UV-visible spectrophotometry using pyrene and N-(4-nitrophenyl) perfluorononanamide, respectively, as molecular probes. The values of the cmc's obtained were considerably different with the two techniques employed. Measurements of the (19)F nuclear magnetic resonance chemical shift of the same mixtures showed two breaks in the plots of Δδ(f) versus molar fraction of the perfluorinated surfactant. Conductivity and surface tension measurements also showed two breaks. The behavior is attributed to the formation of mixed micelles that change their composition when the fraction of the fluorinated compound increases and some segregation of the fluorinated compound takes place at a high total surfactant concentration.

Morphology and Stability of CO2-in-Water Foams with Nonionic Hydrocarbon Surfactants

The morphologies, stabilities, and viscosities of high-pressure carbon dioxide-in-water (C/W) foams (emulsions) formed with branched nonionic hydrocarbon surfactants were investigated by in situ optical microscopy and capillary rheology. Over two dozen hydrocarbon surfactants were shown to stabilize C/W foams with Sauter mean bubble diameters as low as 1 to 2 microm. Coalescence of the C/W foam bubbles was rare for bubbles larger than about 0.5 microm over a 60 h time frame, and Ostwald ripening became very slow. By better blocking of the CO(2) and water phases with branched and double-tailed surfactants, the interfacial tension decreases, the surface pressure increases, and the C/W foams become very stable. For branched surfactants with propylene oxide middle groups, the stabilities were markedly lower for air/water foams and decane-water emulsions. The greater stability of the C/W foams to coalescence may be attributed to a smaller capillary pressure, lower drainage rates, and a sufficient surface pressure and thus limiting surface elasticity, plus small film sizes, to hinder spatial and surface density fluctuations that lead to coalescence. Unexpectedly, the foams were stable even when the surfactant favored the CO(2) phase over the water phase, in violation of Bancroft's rule. This unusual behavior is influenced by the low drainage rate, which makes Marangoni stabilization of less consequence and the strong tendency of emerging holes in the lamella to close as a result of surfactant tail flocculation in CO(2). The high distribution coefficient toward CO(2) versus water is of significant practical interest for mobility control in CO(2) sequestration and enhanced oil recovery by foam formation.

Effect of branching on the interfacial properties of nonionic hydrocarbon surfactants at the air–water and carbon dioxide–water interfaces

The interfacial tensions, surface pressures, and adsorption of nonionic hydrocarbon surfactants at the air–water (A–W) and carbon dioxide–water (C–W) interfaces were investigated systematically as a function of the ethylene oxide (EO) unit length and tail structure. Major differences in the properties are explained in terms of the driving force for surfactant adsorption, tail solvation, area per surfactant molecule, and surfactant packing. As the surfactant architecture is varied, the changes in tail–tail interactions, steric effects, areas occupied by the surfactant at the interface, and tail hydrophobicity are shown to strongly influence the interfacial properties, including the surfactant efficiency (the concentration to produce 20 mN/m interfacial tension reduction). For linear surfactants at the A–W interface, high efficiencies result from dense monolayers produced by the high interfacial tension driving force for adsorption and strong tail–tail interactions. At the C–W interface, where a low interfacial tension leads to a much lower surfactant adsorption, the contact between the phases is much greater. Branching or increasing the number of tail chains increase the hydrophobicity, tail solvation, and adsorption of the surfactant. Furthermore, the area occupied by the surfactant increases with branching, number of tails, and number of EO monomers in the head group, to reduce contact of the phases. These factors produce greater efficiencies for branched and double tail surfactants at the C–W interface, as well as surfactants with longer EO head groups.

Ellipsometric study of the displacement of milk proteins from the oil–water interface by the non-ionic surfactant C10E8

Ellipsometry was employed to study the adsorption to the hexadecane-water interface of the simple non-ionic hydrocarbon surfactant C(10)E(8) and the two milk proteins beta-casein and beta-lactoglobulin, as well as the competitive adsorption of each protein with the surfactant. The interfacial excess of the pure surfactant was determined by tensiometry. Modelling of the ellipsometric response of the pure surfactant monolayer shows that the polyethylene oxide headgroups are hydrated with approximately 40% of the headgroup layer occupied by water. Adsorbed layers of C(10)E(8) at the hexadecane-water, triolein-water and air-water interfaces are structurally similar. Both proteins form dense layers at the oil-water interface with a volume fraction of water in the protein film of <60%. Competitive adsorption between the surfactant and protein was investigated in two ways: co-adsorption from solution or injection of surfactant solution into the subphase of a preformed protein film. The long-time ellipsometric response was independent of the preparation procedure. The protein and surfactant films at oil-water interfaces generate ellipticities of opposite sign, which enabled direct determination of the concentration at which the surfactant completely displaces protein from the interface.

Electroless Ni-plating on PTFE fine particles

A Ni electroless plating process was used with polytetrafluoroethylene (PTFE) fine particles (25–500 μm). Using nonionic hydrocarbon surfactant, PTFE particles were dispersed in the plating bath. The PTFE hydrophobicity was sufficiently high that Ni was deposited partly on the PTFE surface in the initial step. The Ni-PTFE particles were formed into the Ni-PTFE plate by heat treatment at 350 °C after pressing. The Ni-PTFE plate had electrical conductivity and gas permeability, which were influenced by the pore distribution in the plate. Pores with 1 μm diameter might be especially important to impart high gas permeability to the Ni-PTFE plate.

Synthesis of Poly(Methylmethacrylate) Latex with Enhanced Rigidity through Surfactant Control

AbstractWater-based polymer latexes have attracted much attention since their invention in the early 1950s. Its advantages for both general health and the environment were recognized as they emit far less volatile organic compounds (VOCs) than their solvent-based counterparts.The performance of latex paints and coatings is directly proportional to the ease of particle deformation. This is the main driving force for the paints and coatings industry to focus its research efforts towards understanding its mechanism.In contrast, little has been published with respect to enhancing latex's resistance against deformation despite such needs in applications such as templating porous ceramics for catalysis and biomaterial engineering. Specifically, the latex's resistance to deformation is crucial to retain a network of uniform pores for applications relating to enzyme immobilization and materials reinforcement.The current study reports increased heat-resistance observed in latexes when synthesized using a rigid surfactant, dimethyl siloxane – ethylene oxide block copolymer (PDMS-PEO). The film formation process for this latex was deduced using atomic force microscopy and subsequent roughness analysis. A comparative study using a non-ionic long-chain hydrocarbon surfactant, morpholine oleate, was also conducted.

Adsorption Kinetics in Binary Surfactant Mixtures Studied with External Reflection FTIR Spectroscopy

The adsorption kinetics of mixtures of soluble surfactants at the air-water interface was studied on an overflowing cylinder. Vibrational spectra of the adsorbed monolayers were acquired by external reflection Fourier transform infrared spectroscopy, and target factor analysis was used to determine the compositions of mixed monolayers. Laser Doppler velocimetry was employed to measure the surface expansion rates, and hence the effective surface age, which was in the range 0.1-1 s. Three surfactant mixtures with different interactions were investigated. Blends of the cationic hydrocarbon surfactant hexadecyl trimethylammonium bromide (CTAB) and the nonionic hydrocarbon surfactant octaethylene glycol monodecyl ether (C10E8) were found to mix ideally in the monolayer over a wide range of subsurface compositions. Combinations of C10E8 and the anionic fluorosurfactant ammonium perfluorononanoate (APFN) exhibited nonideal mixing that could be described with regular solution theory. APFN adsorbed to the interface at a rate limited by monomer diffusion but the adsorption of C10E8 appeared to be under kinetic control. The adsorption behavior of the cationic-anionic mixture of CTAB and APFN was dominated by the interaction of the oppositely charged headgroups. Either side of equimolar bulk composition only the species in excess was found to adsorb, which is rationalized by the presence of aggregates in the bulk that act as a sink for free monomer. Prior evidence in the literature suggests these aggregates may be vesicles. At equimolar compositions both species were found to coadsorb; this unexpected result may be explained by adsorption of vesicles to the uncharged interface. A semiquantitative model based on the interaction between the electrical double layers of the oppositely charged monolayer and vesicle explains the absence of adsorption of vesicles away from equimolar compositions. The combination of the overflowing cylinder, to generate a steadily expanding surface with well-defined hydrodynamics, and FTIR spectroscopy, to quantify the composition of the adsorbed monolayer, can be used to study a broad range of mixed monolayers at the air-water interface under nonequilibrium conditions.

High internal phase CO2-in-water emulsions stabilized with a branched nonionic hydrocarbon surfactant

A nonionic-methylated branched hydrocarbon surfactant, octa(ethylene glycol) 2,6,8-trimethyl-4-nonyl ether (5b-C12E8) emulsifies up to 90% CO2 in water with polyhedral cells smaller than 10 μm, as characterized by optical microscopy. The stability of these concentrated CO2/water (C/W) emulsions increases with pressure and in some cases exceeds 24 h. An increase in pressure weakens the attractive van der Waals interactions between the CO2 cells across water and raises the disjoining pressure. It also enhances the solution of the surfactant tail and drives the surfactant from water towards the water–CO2 interface, as characterized by the change in emulsion phase behavior and the decrease in interfacial tension (γ) to 2.1 mN/m. As the surfactant adsorption increases, the greater tendency for ion adsorption is likely to increase the electrostatic repulsion in the thin lamellae and raise the disjoining pressure. As pressure increases, the increase in disjoining pressure and decrease in the capillary pressure (due to the decrease in γ) each favor greater stability of the lamellae against rupture. The electrical conductivity is predicted successfully as a function of Bruggeman's model for concentrated emulsions. Significant differences in the stability are observed for concentrated C/W emulsions at elevated pressure versus air/W or C/W foams at atmospheric pressure.

Miscibility of Hydrocarbon and Fluorocarbon Surfactants in Adsorbed Film and Micelle

We investigated the miscibility of nonionic hydrocarbon and fluorocarbon surfactants in the adsorbed film and the micelle by surface tension measurements of the aqueous solution. The combination of tetraethyleneglycol monodecyl ether (C10E4) and tetraethyleneglycol mono-1,1,7-trihydrododecafluoroheptyl ether (FC7E4) was chosen because they have the same hydrophilic groups and about the same surface activity. The extent of nonideal mixing was estimated quantitatively in terms of the excess Gibbs energy in the adsorbed film gH,E and that in the micelle gM,E. The excess area per adsorbed molecule, AH,E, was also evaluated and discussed. The ionic hydrocarbon and fluorocarbon mixed surfactant systems, lithium dodecyl sulfate (LiDS)/lithium perfluorooctane sulfonate (LiFOS) and lithium tetradecyl sulfate (LiTS)/LiFOS systems are also investigated from the standpoint of excess Gibbs energy and excess area. It is also clearly shown that the regular solution approach does not fit in the systems that contain ionic species.